Netega two-component integrated wood plywood adhesive use precautions

The adhesive strength is weakened

Phenomenon analysis At high temperature in summer, the drying speed of the surface of the glue is accelerated, and the bonding strength of the glue will be reduced by about 10-20% compared with the viscosity at room temperature. It should be noted that the viscosity of the adhesive is its own physical characteristics, and its bonding force is the bonding strength reflected in the bonding of the object, and there is no direct relationship between the two. Adhesives with high viscosity do not necessarily stick well. In other words, viscosity ≠ adhesion. However, the bonding strength will still affect the adhesion of the glue to a certain extent, so it should be paid attention to during construction.

Countermeasures Netega plywood glue in the premise of ensuring the amount of glue, less mixing and quick use; It is recommended that the amount of glue should be used within 30 minutes each time; Applying glue during the active period does not affect the bonding strength of the glue, but exceeding the active period will cause the bonding strength of the glue to weaken. The crosslinking reaction is obviously accelerated.

Phenomenon analysis, the crosslinking reaction will occur after the mixing of plywood glue. After the chemical reaction between the isocyanate group (-NCO) in the curing agent and the hydroxyl group (-OH) in the main agent and the hydroxyl group (-OH) in the wood, the complex giant molecular structure is formed. The degree of the chemical reaction has a direct influence on the bonding strength and the water resistance of the plywood. When entering the high temperature season in summer, the high temperature will promote the cross-linking reaction to accelerate significantly, and whether the mixed plywood can be used in a short time will directly affect the splicing effect of wood. The plywood glue mixed with curing agent should be used up within 30 minutes, so as to avoid product problems caused by subsequent glue adhesion decline when the reaction is close to completion.

The drying speed is accelerated, and it is easy to have false bonding problems

Phenomenon analysis When the summer temperature is high, the molecular activity of the plywood glue is enhanced, and the glue becomes thinner due to high temperature, which on the one hand will speed up the drying speed, on the other hand, it may also lead to insufficient glue in the local area. If the amount of glue is too little, or the time for gluing and stacking pressure is too long, the glue will exceed its active period, and the glue layer will form a film due to drying, leading to false bonding problems.

The countermeasures require the operator to be skilled; Under the premise of ensuring the amount of glue, less mixing and quick use, it is better to complete the pressure operation in about 3-5 minutes after gluing, to ensure that the glue does not appear on the surface of the film, which is prone to false adhesion phenomenon, resulting in quality problems; It is not recommended to use plywood glue that has exceeded the active period.

Foaming phenomenon increased significantly

Phenomenon analysis in high temperature weather in summer, after adding curing agent to the plywood glue, the foaming speed will be faster than other seasons, in the active period, does not affect the activity period of the glue, does not affect the normal use of the glue. However, if the ratio is too much, the activity period of the adhesive will be shortened, and the foaming phenomenon of the adhesive will be significantly enhanced.

When the problem is encountered, stir it again to reduce the foaming phenomenon; Under the working condition of high temperature, the curing agent can be reduced by 2% ~ 3% by rationally controlling the proportion of curing agent; Fewer times, each time the amount of mixing should be used within 30 minutes is better. (The sooner you use it, the better)